Clinical Indicators and Imaging Characteristics of Blunt Traumatic Diaphragmatic Injury: A Retrospective Single-Center Study

<b>Background/Objectives:</b> Blunt trauma injury of the diaphragm is uncommon. Even after imaging examination, accurate diagnosis remains difficult. We sought to identify clinical factors that raise suspicion of such injuries, which can be applied during the initial evaluation of trauma patients. <b>Methods:</b> We retrospectively analyzed patients with blunt trauma who were diagnosed with diaphragmatic injury between January 2015 and July 2025. Demographic variables, clinical findings, operative records, and imaging findings were reviewed. <b>Results:</b> The most common mechanism of injury in patients with diaphragmatic injury was traffic accidents (64.2%), and 77.4% were identified as severe injuries with an Injury Severity Score (ISS) ≥ 16. Computed tomography (CT) scans of these patients frequently showed hemothorax, hemoperitoneum, and pneumothorax, but 49.1% of cases did not show diaphragmatic injury on preoperative imaging. In these patients, pneumothorax, lower rib fractures, and liver injury were more common. Notably, pneumothorax strongly suggested the possibility of diaphragmatic injury in patients where intrathoracic herniation was not clear. <b>Conclusions:</b> In patients with polytrauma and unstable vital signs, CT evaluation of torso injuries and careful interpretation are essential. Even when CT does not reveal diaphragmatic injury, suspicion should be elevated in cases with high ISS accompanied by pneumothorax, hemoperitoneum, hemothorax, lower rib fractures, or extremity injuries. If the injury mechanism further raises clinical suspicion, repeated physical examinations and imaging studies should be performed. When suspicion remains high, surgical intervention should be considered to confirm the diagnosis.